New features in Java 12: How to use the new String API to intercept and concatenate strings

As a widely used programming language, Java has been continuously developed and updated. Each new version will introduce some new features and functions to improve developers' coding efficiency. One of the features of Java 12, the latest version, is the introduction of the new String API, which makes string interception and concatenation more convenient and efficient.

In previous versions, string interception and concatenation operations needed to be implemented by calling substring() and the " " operator. However, these methods had poor performance when processing a large number of string operations and easily caused memory problems. Overflow and performance degradation issues. The new String API introduced in Java 12 provides a more efficient and concise way to intercept and concatenate strings.

First, let us take a look at how to use the new String API to intercept strings. In Java 12, we can use the new String class method: substring​(int beginIndex, int endIndex) to implement string interception. Compared with the previous substring() method, this method provides more flexible parameter settings and can intercept the string based on the starting position and ending position. The following is a simple sample code:

String str = "Hello, world!";
String subStr = str.substring(7, 12);
System.out.println(subStr); // 输出：world

In the above code, we define a string str, and then use the substring() method to intercept from position 7 to position 12, and get a new substring subStr. Finally, by printing subStr, we can see that the result correctly outputs "world".

Next, let’s take a look at how to use the new String API to concatenate strings. In Java 12, we can use the new String class method: concat(CharSequence str) to achieve string concatenation. Compared with the previous " " operator, this method performs better in terms of performance and readability. The following is a simple sample code:

String str1 = "Hello,";
String str2 = " world!";
String str3 = str1.concat(str2);
System.out.println(str3); // 输出：Hello, world!

In the above code, we define two strings str1 and str2, and then use the concat() method to connect them to get a new string str3. Finally, by printing str3, we can see that the result correctly outputs "Hello, world!".

In addition to string interception and concatenation, the new String API in Java 12 also provides many other useful methods, such as the repeat(int count) method for repeating strings, and the strip() method for Remove leading and trailing spaces from a string. The isBlank() method is used to determine whether it is a blank string, etc. The introduction of these methods makes string operations more convenient and efficient.

To sum up, the new String API introduced in Java 12 provides a more flexible and efficient way to intercept and connect strings. By using the new substring​() and concat() methods, we can implement string operations concisely and avoid performance issues that may have occurred in previous versions. As Java developers, we should master and apply these new features in a timely manner to improve our coding efficiency and quality.

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